Panmunjom was designated as the center of a circular neutral zone of a 1,000 yard radius, and a three mile radius around Munsan and Kaesong was also neutralized, as well as two hundred meters on either side of the Kaesong-Munsan road.[28] [28] Rees, _Korea_, p. 295. To prevent the occurrence of any hostile act within this sanctuary, Lieutenant General John W. O’Daniel, I Corps commander, ordered that an additional area, forward of the OPLR, be set aside. This megaphone-shaped zone “could not be fired into, out of, or over.”[29] It was adjacent to the OPLR in the division center regimental sector, near its left boundary, and took a generally northwest course. Marines reported that the Communists knew of this restricted zone and frequently used it for assembly areas and artillery emplacements. [29] 1stMarDiv ComdD, Mar 52, p. 7. _The 1st Marine Aircraft Wing_[30] [30] Unless otherwise noted, the material in this section is derived from _PacFlt EvalRpt_ No. 4, Chap. 10; 1stMarDiv ComdD, Mar 52; 1st MAW ComdDs, Mar-Apr 52. When the 1st Marine Division moved to western Korea in March 1952, the two 1st Marine Aircraft Wing units that had been in direct support of the ground Marines also relocated. Marine Observation Squadron 6 (VMO-6) and Marine Helicopter Transport Squadron 161 (HMR-161) completed their displacements by 24 March from their eastern airfield (X-83) to sites in the vicinity of the new division CP. HMR-161, headed by Colonel Keith B. McCutcheon, set up headquarters at A-17,[31] on a hillside 3½ miles southeast of Munsan-ni, the division railhead, “using a couple of rice paddies as our L. Z. (Landing Zone).”[32] The squadron rear echelon, including the machine shops, was maintained at A-33, near Ascom City. About 2½ miles south of the helicopter forward site was an old landing strip, A-9, which Lieutenant Colonel William T. Herring’s observation squadron used as home field for its fixed and rotary wing aircraft. (For location of 1st MAW units see Map 4.) In West Korea, VMO-6 and HMR-161 continued to provide air transport for tactical and logistical missions. Both squadrons were under operational control of the division, but administered by the wing. [31] In Korea, fields near U.S. Army installations were known as “A”; major airfields carried a “K” designation; and auxiliary strips were the “X” category. [32] MajGen Keith B. McCutcheon comments on draft MS, dtd 1 Sep 66.